1. Field of the Invention
The present invention relates to an ink-jet head for ejecting ink onto a record medium to print, a filter assembly used for the ink-jet head, and a method for manufacturing the ink-jet head using the filter assembly.
2. Description of Related Art
In an ink-jet head, ink in an ink tank is lead to a supply passage, a common ink chamber, a pressure chamber, and then to a nozzle for ejecting the ink. Such a ink passage is formed by laminating a plurality of plates each formed with grooves or holes.
An ink-jet head, in terms of printing quality, needs to include a filter for removing foreign matters mixed in ink. Thus, there are known such techniques that a filter is formed in a plate serving as a boundary between a supply passage and a common ink chamber, among the plurality of plates constituting the above-mentioned ink passage (See Japanese Patent Laid-Open No. 6-255101), and that a filter is formed in a communicating region of a common ink chamber and a pressure chamber (See Japanese Patent Laid-Open No. 2-198851).
However, in case that a filter is formed in a plate serving as a boundary between a supply passage and a common ink chamber, the filter needs to be formed corresponding to each common ink chamber, and in case that a filter is formed in a communicating region of a common ink chamber and a pressure chamber, the filter needs to be formed corresponding to each pressure chamber. As a result, each filter becomes relatively small in size and relatively large in number. In these cases, a dimensional error of the filter is often caused. This dimensional error causes a variation of passage resistance in the individual ink passage each corresponding to an individual nozzle, thereby leading to deterioration of printing quality.